The subject matter of the present disclosure broadly relates to the art of fluid suspension systems. It finds particular application in conjunction with gas spring assemblies such as are commonly used in vehicle suspension systems, and will be described herein with particular reference thereto. However, it is to be appreciated that the subject matter of the present disclosure is capable of broad use in a wide variety of applications and environments and that the specific reference herein to use in vehicle suspension systems is merely exemplary.
Vehicle suspension systems typically include a plurality of spring elements for accommodating forces and loads associated with the operation and use of the vehicle. In such vehicle suspension system applications, it is often considered desirable to select spring elements that have the lowest suitable spring rate, as this favorably influences ride quality and comfort. That is, it is well understood in the art that the use of spring elements having higher spring rates (i.e., stiffer springs) will transmit a greater magnitude of road inputs into the sprung mass of the vehicle and that this typically results in a rougher, less-comfortable ride. Whereas, the use of spring elements having lower spring rates (i.e., softer, more-compliant springs) will transmit a lesser amount of the road inputs to the sprung mass and will, thus, provide a more comfortable ride.
With more specific reference to gas springs, it is possible to reduce the spring rate of gas springs, thereby improving ride comfort, by increasing the volume of pressurized gas operatively associated with the gas spring. This is commonly done by placing an additional chamber, cavity or volume filled with pressurized gas into fluid communication with the primary spring chamber of the gas spring, as is well known by those of skill in the art. Such additional volumes can be formed within a component of the gas spring itself, as shown, for example, in U.S. Pat. No. 5,954,316, or provided separately and connected through one or more passages, as shown, for example, in U.S. Pat. No. 6,691,989.
While it is known to increase the volume of the pressurized gas associated with the gas spring by providing external reservoirs or fluidly connecting a piston chamber with the main spring chamber, such approaches include certain disadvantages that may have limited the adoption and use thereof. For example, providing a remote reservoir generally involves mounting a separate reservoir and connecting it to the main spring chamber via a hose or the like. This approach introduces additional potential leak points, and requires additional steps in the manufacturing and/or assembly processes. Providing additional volume by connecting the main spring chamber to a piston chamber can provide suitable results in some applications, but the additional volume that can be added is often limited by mounting constraints. For example, past piston designs generally include a planar mounting surface on the bottom of the piston for mounting the piston to a corresponding planar support member. Given the generally tight spaces in which such pistons are often mounted, the additional volume added to the spring chamber is often limited to the volume of the piston chamber that is located above the mounting surface.
Accordingly, it is believed desirable to develop a gas spring piston as well as a gas spring assembly and vehicle suspension system that include such a gas spring piston that obviate the foregoing and/or other disadvantages of known constructions.